Diagnostic Accuracy of Bone Culture Versus Biopsy in Diabetic Foot Osteomyelitis

Evaluating diagnostic tools, outcome measures and antibiotic approach in diabetic foot osteomyelitis: a scoping review and narrative synthesis

INTRODUCTION

Diabetic foot osteomyelitis (DFO) is a significant complication of diabetic foot disease; however, diagnosis remains challenging and treatment success is difficult to ascertain. Literature in this space that has utilized varying diagnostic criteria and ideal outcome measures for success is unclear.

AREAS COVERED

This scoping review assesses methods of diagnosis of DFO and definitions of treatment outcomes in the literature assessing antibiotic therapy for treatment of DFO.

EXPERT OPINION

There is a lack of consensus in the design of diabetic foot trials, resulting in difficulty for clinicians to assess and manage serious conditions such as DFO. The cure for DFO is challenging to ascertain and treatment failure may be a better approach to assess outcomes in research assessing the efficacy of antibiotic therapy. In the absence of gold-standard diagnostic tools, practical approaches to outcome assessment may allow for greater clinical applicability of available data.

BedBiopsy: Diagnostic performance of bedside ultrasound-guided bone biopsies for the management of diabetic foot infection

OBJECTIVE

We aimed to assess the feasibility and diagnostic performance of ultrasound-guided bone biopsies at the bedside of diabetic patients admitted for suspected foot osteitis not requiring surgery.

RESEARCH DESIGN AND METHODS

In this retrospective monocentric study, we compared the performance of ultrasound-guided (n = 29 consecutive patients, Dec.2020-Oct.2022) versus surgical (n = 24 consecutive patients, Jan.2018-Nov.2020) bone biopsies at confirming or ruling out diabetic foot osteitis (primary outcome).

RESULTS

Patient characteristics were similar in the two intervention groups, including arteritis prevalence (62.3 %), SINBAD score, and wound location (phalanges 36 %, metatarsus 43 %, and calcaneus 21 %). However, the ultrasound-guided group was older (67 ± 11 versus 60 ± 13 years respectively, P = 0.047) and had more type 2 diabetes (97 % versus 75 %, P = 0.038). Diagnostic performance (i.e., capacity to confirm or rule out suspected osteitis) was similar for ultrasound-guided (28/29 cases: 25 confirmations, 3 invalidations) and surgical (24 confirmations/24) biopsies, P = 0.358. No biopsy-related side effect or complication was observed for either intervention, even for patients on antiaggregation and/or anticoagulation therapy. The mean (± standard deviation) time necessary to perform the biopsy was shorter in the ultrasound-guided group (2.6 ± 3.0 versus 7.2 ± 5.8 days, respectively, P < 0.001) and wound evolution at three months was more favorable (83.3 versus 41.2 %, P = 0.005) (94.4 % versus 66.7 %, respectively, patients with new surgical procedure within six months excluded; P = 0.055). Even though not statistically significant, healing rates in terms of wound and osteitis at six months were also better in the ultrasound-guided group (wound: 40.9 % versus 36.8 %; P = 0.790, and osteitis: 81.8 vs 55.6 % P = 0.071).

CONCLUSION

In diabetic patients with suspected foot osteitis not requiring surgery, bedside ultrasound-guided bone biopsies may constitute a promising alternative to surgical biopsies. This intervention provided excellent tolerance and microbiological documentation, short lead-times, and more favorable wound prognosis.

Diagnosis of infection in the foot of patients with diabetes: A systematic review

BACKGROUND

Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potential mortality and present formidable challenges in surgical and antimicrobial treatment.

METHODS

In June 2022, we searched the literature using PubMed and EMBASE for published studies on the diagnosis of diabetic foot infection (DFI). On the basis of pre-determined criteria, we reviewed prospective controlled, as well as non-controlled, studies in English. We then developed evidence statements based on the included papers.

RESULTS

We selected a total of 64 papers that met our inclusion criteria. The certainty of the majority of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot/Infectious Diseases Society of America scheme correlates with the patient's likelihood of the need for hospitalisation, lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein and procalcitonin are supportive, but not diagnostic, of soft tissue infection. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Although non-culture techniques, especially next-generation sequencing, are likely to identify more bacteria from tissue samples including bone than standard cultures, no studies have established a significant impact on the management of patients with DFIs. In patients with suspected diabetic foot osteomyelitis, the combination of a positive probe-to-bone test and elevated ESR supports this diagnosis. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis (DFO), but advanced imaging methods including magnetic resonance imaging (MRI) and nuclear imaging when MRI is not feasible help in cases when either the diagnosis or the localisation of infection is uncertain. Intra-operative or non-per-wound percutaneous biopsy is the best method to accurately identify bone pathogens in case of a suspicion of a DFO. Bedside percutaneous biopsies are effective and safe and are an option to obtain bone culture data when conventional (i.e. surgical or radiological) procedures are not feasible.

CONCLUSIONS

The results of this systematic review of the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is still a need for more prospective controlled studies of high quality.

IWGDF/IDSA guidelines on the diagnosis and treatment of diabetes-related foot infections (IWGDF/IDSA 2023)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the management and prevention of diabetes-related foot diseases since 1999. The present guideline is an update of the 2019 IWGDF guideline on the diagnosis and management of foot infections in persons with diabetes mellitus. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used for the development of this guideline. This was structured around identifying clinically relevant questions in the P(A)ICO format, determining patient-important outcomes, systematically reviewing the evidence, assessing the certainty of the evidence, and finally moving from evidence to the recommendation. This guideline was developed for healthcare professionals involved in diabetes-related foot care to inform clinical care around patient-important outcomes. Two systematic reviews from 2019 were updated to inform this guideline, and a total of 149 studies (62 new) meeting inclusion criteria were identified from the updated search and incorporated in this guideline. Updated recommendations are derived from these systematic reviews, and best practice statements made where evidence was not available. Evidence was weighed in light of benefits and harms to arrive at a recommendation. The certainty of the evidence for some recommendations was modified in this update with a more refined application of the GRADE framework centred around patient important outcomes. This is highlighted in the rationale section of this update. A note is also made where the newly identified evidence did not alter the strength or certainty of evidence for previous recommendations. The recommendations presented here continue to cover various aspects of diagnosing soft tissue and bone infections, including the classification scheme for diagnosing infection and its severity. Guidance on how to collect microbiological samples, and how to process them to identify causative pathogens, is also outlined. Finally, we present the approach to treating foot infections in persons with diabetes, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and bone infections; when and how to approach surgical treatment; and which adjunctive treatments may or may not affect the infectious outcomes of diabetes-related foot problems. We believe that following these recommendations will help healthcare professionals provide better care for persons with diabetes and foot infections, prevent the number of foot and limb amputations, and reduce the patient and healthcare burden of diabetes-related foot disease.

IWGDF/IDSA Guidelines on the Diagnosis and Treatment of Diabetes-related Foot Infections (IWGDF/IDSA 2023)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the management and prevention of diabetes-related foot diseases since 1999. The present guideline is an update of the 2019 IWGDF guideline on the diagnosis and management of foot infections in persons with diabetes mellitus. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was used for the development of this guideline. This was structured around identifying clinically relevant questions in the P(A)ICO format, determining patient-important outcomes, systematically reviewing the evidence, assessing the certainty of the evidence, and finally moving from evidence to the recommendation. This guideline was developed for healthcare professionals involved in diabetes-related foot care to inform clinical care around patient-important outcomes. Two systematic reviews from 2019 were updated to inform this guideline, and a total of 149 studies (62 new) meeting inclusion criteria were identified from the updated search and incorporated in this guideline. Updated recommendations are derived from these systematic reviews, and best practice statements made where evidence was not available. Evidence was weighed in light of benefits and harms to arrive at a recommendation. The certainty of the evidence for some recommendations was modified in this update with a more refined application of the GRADE framework centred around patient important outcomes. This is highlighted in the rationale section of this update. A note is also made where the newly identified evidence did not alter the strength or certainty of evidence for previous recommendations. The recommendations presented here continue to cover various aspects of diagnosing soft tissue and bone infections, including the classification scheme for diagnosing infection and its severity. Guidance on how to collect microbiological samples, and how to process them to identify causative pathogens, is also outlined. Finally, we present the approach to treating foot infections in persons with diabetes, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and bone infections; when and how to approach surgical treatment; and which adjunctive treatments may or may not affect the infectious outcomes of diabetes-related foot problems. We believe that following these recommendations will help healthcare professionals provide better care for persons with diabetes and foot infections, prevent the number of foot and limb amputations, and reduce the patient and healthcare burden of diabetes-related foot disease.

State-of-the-art update for diagnosing diabetic foot osteomyelitis: a narrative review

Recently, the International Working Group on the Diabetic Foot and the Infectious Diseases Society of America divided diabetic foot disease into diabetic foot infection (DFI) and diabetic foot osteomyelitis (DFO). DFI is usually diagnosed clinically, while numerous methods exist to diagnose DFO. In this narrative review, the authors aim to summarize the updated data on the diagnosis of DFO. An extensive literature search using "diabetic foot [MeSH]" and "osteomyelitis [MeSH]" or "diagnosis" was performed using PubMed and Google Scholar in July 2023. The possibility of DFO is based on inflammatory clinical signs, including the probe-to-bone (PTB) test. Elevated inflammatory biochemical markers, especially erythrocyte sedimentation rate, are beneficial. Distinguishing abnormal findings of plain radiographs is also a first-line approach. Moreover, sophisticated modalities, including magnetic resonance imaging and nuclear medicine imaging, are helpful if doubt remains after a first-line diagnosis. Transcutaneous bone biopsy, which does not pass through the wound, is necessary to avoid contaminating the sample. This review focuses on the current diagnostic techniques for DFOs with an emphasis on the updates. To obtain the correct therapeutic results, selecting a proper option is necessary. Based on these numerous diagnosis modalities and indications, the proper choice of diagnostic tool can have favorable treatment outcomes.

Analysis of the Influence of Diabetic Nephropathy in Patients with Diabetic Foot Osteomyelitis

This study analyzed the influence of diabetic nephropathy on the healing prognosis after conservative surgery in diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between January 2021 and December 2022 and involved 278 outpatients with a diagnosis of DFO at a specialized diabetic foot unit, including 74 (26.62%) patients with DN (group 2) and 204 (73.38%) patients without DN (group 1). There were 266 (95.70%) ulcers on the forefoot, 8 (2.90%) on the midfoot, and 4 (1.45%) on the hindfoot (p = 0.992). The healing rates were 85.1% (n = 63) for group 2 and 81.3% (n = 165) for group 1 (p = 0.457). When exploring the influence of DN on the risk of delayed ulcer healing, the results did not show a significant effect [12 (6; 28) weeks among patients with DN vs. 12 (6; 21) weeks among patients without DN; p = 0.576]. No significant differences were observed in complications, with one (2.59%) death occurring in group 1 (p = 0.296) and three minor amputations being performed in both groups [two (5.13%) amputations in group 1 vs. one amputation (9.09%) in group 2; p = 0.217]. Bone cultures were performed for a total of 190 patients (133 in group 1 and 57 in group 2). Of these, 176 positive bone cultures were isolated: 71 positive bone cultures (57.7%) were monomicrobial cultures in group 1, with 30 (56.6%) in group 2. There were 52 (42.3%) that had at least two microorganisms in group 1, and 23 (43.4%) in group 2 (p = 0.890). The most frequently prescribed oral antibiotic was amoxicillin/clavulanate (43.89%), followed by levofloxacin (28.4%), and trimethoprim/sulfamethoxazole (14.7%). This study shows that DN does not have a significant influence on the healing prognosis of patients with DFO after conservative surgery.

Detection, management, and prevention of diabetes-related foot disease in the Australian context

Diabetes-related foot disease (DFD) is a widely feared complication among people who live with diabetes. In Australia and globally, rates of disability, cardio-vascular disease, lower extremity amputation, and mortality are significantly increased in patients with DFD. In order to understand and prevent these outcomes, we analyse the common pathogenetic processes of neuropathy, arterial disease, and infection. The review then summarises important management considerations through the interdisciplinary lens. Using Australian and international guidelines, we offer a stepwise, evidence-based practical approach to the care of patients with DFD.

Bacterial Diversity and Antibiotic Resistance in Patients with Diabetic Foot Osteomyelitis

This study analysed the bacterial diversity, antibiotic susceptibility, and resistance in patients with complications of diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between September 2019 and September 2022 and involved 215 outpatients with a diagnosis of DFO at a specialized diabetic foot unit. A total of 204 positive bone cultures were isolated, including 62.7% monomicrobial cultures, and 37.3% were formed with at least two microorganisms. We observed that Proteus spp., Coagulase-negative staphylococci (CoNS), Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Corynebacterium were the most frequently isolated microorganisms and accounted for more than 10% of the DFO cases. With stratification by Gram-positive (GP) and Gram-negative (GN) bacteria, we observed that 91.6% of cultures presented at least one GP bacteria species, and 50.4% presented at least one GN bacteria species. The most common GP species were CoNS (29%), S. aureus (25.8%), and Corynebacterium spp. (14%). The most frequent GN species consisted of Proteus spp. (32%), P. aeruginosa (23.3%), and E. coli (17.5%). The main antibiotics with resistance to GP-dominated infections were penicillins without β-lactamase inhibitor, and those in GN-dominated infections were sulfonamides and penicillins without β-lactamase. Significant differences were not observed in mean healing time in DFU with acute osteomyelitis (12.76 weeks (4.50;18)) compared to chronic osteomyelitis (15.31 weeks (7;18.25); p = 0.101) and when comparing cases with soft tissue infection (15.95 (6;20)) and those without such an infection (16.59 (7.25;19.75), p = 0.618). This study shows that when treatment of DFO is based on early surgical treatment, the type of DFO and the presence of soft infection are not associated with different or worse prognoses.

Variables That Could Influence Healing Time in Patients with Diabetic Foot Osteomyelitis

AIM

To compare the healing time in patients with diabetic foot osteomyelitis according to the presence or absence of clinical signs of infection, variation of blood parameters, the presence of different radiological signs, and the treatment received for the management of osteomyelitis.

METHODS

A prospective observational study was carried out in a specialised Diabetic Foot Unit between November 2014 and November 2018. A total of 116 patients with osteomyelitis were included in the study (treated by either a surgical or medical approach). During the baseline visit, we assessed the diagnosis of osteomyelitis, demographic characteristics and medical history, vascular and neurological examination, clinical signs of infection, increased blood parameters, radiological signs of osteomyelitis, and the treatment to manage osteomyelitis. We analysed the association between the presence of clinical signs of infection, variation of blood parameters, presence of radiological signs, and treatment received for management of osteomyelitis with the healing time.

RESULTS

The mean time to ulcer healing was 15.8 ± 9.7 weeks. Concerning healing times, we did not find an association with the presence of clinical signs of infection or with the increase in blood parameters, except in the case of eosinophils, which with higher values appear to increase the healing time (U = 66, z = -2.880, p = 0.004). Likewise, no relationship has been found between healing time and the appearance of the different radiological signs of osteomyelitis, nor depending on the treatment administered for the management of osteomyelitis.

CONCLUSION

High levels of eosinophils are associated with a longer healing time of diabetic foot ulcers complicated with osteomyelitis, finding no other factors related to increased healing time.

Could X-ray Predict Long-term Complications in Patients with Diabetic Foot Osteomyelitis?

OBJECTIVE

To analyze the association between radiologic changes on plain X-rays in patients with diabetic foot osteomyelitis and the development of complications at the 1-year follow-up.

METHODS

A prospective, observational study was conducted involving 115 patients with diabetic foot osteomyelitis. X-ray features that were evaluated during 1-year follow-up visits included affected bone marrow, active periosteal reaction, sequestrum, cortical disruption, and other types of signs. Researchers analyzed the association between the presence of X-ray changes and complication development, such as bone or soft tissue infections, ulcer recurrence, reulceration, amputation, death, and other diabetic foot disease-related events.

RESULTS

During follow-up, of 115 patients included in the study, 33 patients (28.7%) showed radiologic changes, and 85 (73.9%) developed complications. The presence of radiologic changes after ulcer healing had a significant association with complication development during the 1-year follow-up in addition to those found at different follow-up visits. Patients who showed radiologic changes had higher percentages of complications during the 1-year follow-up, and patients without radiologic changes had lower percentages of complications.

CONCLUSIONS

The presence of radiologic changes is related to the development of complications in patients who suffer from diabetic foot osteomyelitis.

Are Digital Arthroplasty and Arthrodesis Useful and Safe Surgical Techniques for the Management of Patients with Diabetic Foot?

OBJECTIVE

To analyze and compare the development of short- and long-term complications in patients with diabetic foot after digital arthroplasty or arthrodesis.

METHODS

The authors reviewed patient records from January 2017 to March 2020. Patients were treated by digital arthroplasty or arthrodesis to correct toe deformity (elective or prophylactic surgery), achieve ulcer healing in toes (curative surgery), or manage toe infection (emergent surgery). During 1-year follow-up, researchers registered short- and long-term complications. Researchers analyzed the association between the type of surgery and the development of short- and long-term complications.

RESULTS

Forty-four patients (83.0%) received arthroplasty, and nine (17.0%) received arthrodesis. The mean time to heal from ulcers was 5.2 ± 5.2 weeks. A significant association was observed between arthrodesis and the development of long-term complications (P = .044; odds ratio, 5.1; 95% confidence interval, 0.9-27.2). No differences were observed between type of surgery and short- or long-term complications. Moreover, both short- and long-term complications were related to longer time to heal (respectively, 7.6 ± 6.0 vs 2.1 ± 0.5 weeks, P < .001; and 6.3 ± 6.2 vs 4.2 ± 4.0 weeks, P = .039).

CONCLUSIONS

Digital arthroplasty or arthrodesis are good options for managing patients with diabetic foot who require digital deformity correction to achieve digital ulcer healing or management of diabetic foot infection in phalanges.

Surgical Treatment of Diabetic Foot and Ankle Osteomyelitis

A review of the literature regarding the evaluation and management of osteomyelitis and discussion on clinical, radiographic, laboratory, and pathologic findings with both acute and chronic cases is presented. Cases illustrate the complexities that can typically present at an academic setting, which often require a stepwise approach and interdisciplinary collaboration. Surgical pearls and ancillary treatment of osteomyelitis highlight the technical challenges and surgeons' preferences.

Evaluation of Adherence to the Oral Antibiotic Treatment in Patients With Diabetic Foot Infection

Introduction: The knowledge about level of adherence to oral antibiotic treatment in diabetic patients with ulcer infection could be essential as a method of evaluation/monitoring of conservative treatment. Aim: To assess the adherence to oral antibiotic treatment in outpatients with diabetic foot infection (soft tissue vs. osteomyelitis) by 8-item structured, self-reported medication adherence scale. Methods: cross-sectional study was carried out with 46 consecutive patients who had diabetic foot infection (soft tissue or bone infection) and required antibiotic oral treatment at outpatient clinical setting. Medication adherence was tested using the Spanish version of the validated eight-item self-report MMAS-8. Results: patients with diabetic ulcer infection, had well level of adherence to antibiotic medication (7   ±   1.2 vs. 7.4   ±   1.5). Patients with lower level of adherence had lower level of satisfaction with the antibiotic medication. The profile of the patients with lower level of adherence were patients with primary level of education and patient who required more help to take the medication. Conclusion: Patients with diabetic foot infection demonstrated well level of adherence to antibiotic medication, independently of type of infection (soft tissue vs. osteomyelitis) by 8-item structured, self-reported medication adherence scale.

Long-Term Complications after Surgical or Medical Treatment of Predominantly Forefoot Diabetic Foot Osteomyelitis: 1 Year Follow Up

AIM

To compare long-term complications according to the treatment received for management of diabetic foot osteomyelitis (surgical or medical) at 1 year follow up.

DESIGN AND PARTICIPANTS

A prospective observational study was conducted involving 116 patients with diabetic foot osteomyelitis. The patients received surgical or medical treatment based on the principles described in the literature. To register the development of a complication, both groups of treatments were followed-up 1 year after the ulcer had healed.

RESULTS

Ninety-six (82.8%) patients received surgical treatment and 20 (17.2%) medical treatment. No differences were found in the time to healing between both groups of treatment, 15.7 ± 9.2 weeks in the surgical group versus 16.4 ± 12.1 weeks in the medical group; p = 0.103. During follow up, 85 (73.3%) patients developed complications without differences between both groups, 68 (70.8%) in the surgical group versus 17 (85%) in the medical group (p = 0.193). The most common complication in both groups was re-ulceration. We did not observe significant differences comparing complication-free time survival between both treatments (p = 0.665).

CONCLUSION

The onset of complications after healing in patients who suffered from diabetic foot osteomyelitis was not associated with the treatment received. Surgical and medical approaches to the management of diabetic foot osteomyelitis produced similar results in long-term follow up.